1 /*
2 ===========================================================================
3 Copyright (C) 1999 - 2005, Id Software, Inc.
4 Copyright (C) 2000 - 2013, Raven Software, Inc.
5 Copyright (C) 2001 - 2013, Activision, Inc.
6 Copyright (C) 2005 - 2015, ioquake3 contributors
7 Copyright (C) 2013 - 2015, OpenJK contributors
8
9 This file is part of the OpenJK source code.
10
11 OpenJK is free software; you can redistribute it and/or modify it
12 under the terms of the GNU General Public License version 2 as
13 published by the Free Software Foundation.
14
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, see <http://www.gnu.org/licenses/>.
22 ===========================================================================
23 */
24
25 // tr_noise.c
26 #include "tr_common.h"
27
28 #define NOISE_SIZE 256
29 #define NOISE_MASK ( NOISE_SIZE - 1 )
30
31 #define VAL( a ) s_noise_perm[ ( a ) & ( NOISE_MASK )]
32 #define INDEX( x, y, z, t ) VAL( x + VAL( y + VAL( z + VAL( t ) ) ) )
33
34 static float s_noise_table[NOISE_SIZE];
35 static int s_noise_perm[NOISE_SIZE];
36
37 #define LERP( a, b, w ) ( a * ( 1.0f - w ) + b * w )
38
GetNoiseValue(int x,int y,int z,int t)39 static float GetNoiseValue( int x, int y, int z, int t )
40 {
41 int index = INDEX( ( int ) x, ( int ) y, ( int ) z, ( int ) t );
42
43 return s_noise_table[index];
44 }
45
GetNoiseTime(int t)46 float GetNoiseTime( int t )
47 {
48 int index = VAL( t );
49
50 return (1 + s_noise_table[index]);
51 }
52
R_NoiseInit(void)53 void R_NoiseInit( void )
54 {
55 int i;
56
57 srand( 1001 );
58
59 for ( i = 0; i < NOISE_SIZE; i++ )
60 {
61 s_noise_table[i] = ( float ) ( ( ( rand() / ( float ) RAND_MAX ) * 2.0 - 1.0 ) );
62 s_noise_perm[i] = ( unsigned char ) ( rand() / ( float ) RAND_MAX * 255 );
63 }
64 }
65
R_NoiseGet4f(float x,float y,float z,float t)66 float R_NoiseGet4f( float x, float y, float z, float t )
67 {
68 int i;
69 int ix, iy, iz, it;
70 float fx, fy, fz, ft;
71 float front[4];
72 float back[4];
73 float fvalue, bvalue, value[2], finalvalue;
74
75 ix = ( int ) floor( x );
76 fx = x - ix;
77 iy = ( int ) floor( y );
78 fy = y - iy;
79 iz = ( int ) floor( z );
80 fz = z - iz;
81 it = ( int ) floor( t );
82 ft = t - it;
83
84 for ( i = 0; i < 2; i++ )
85 {
86 front[0] = GetNoiseValue( ix, iy, iz, it + i );
87 front[1] = GetNoiseValue( ix+1, iy, iz, it + i );
88 front[2] = GetNoiseValue( ix, iy+1, iz, it + i );
89 front[3] = GetNoiseValue( ix+1, iy+1, iz, it + i );
90
91 back[0] = GetNoiseValue( ix, iy, iz + 1, it + i );
92 back[1] = GetNoiseValue( ix+1, iy, iz + 1, it + i );
93 back[2] = GetNoiseValue( ix, iy+1, iz + 1, it + i );
94 back[3] = GetNoiseValue( ix+1, iy+1, iz + 1, it + i );
95
96 fvalue = LERP( LERP( front[0], front[1], fx ), LERP( front[2], front[3], fx ), fy );
97 bvalue = LERP( LERP( back[0], back[1], fx ), LERP( back[2], back[3], fx ), fy );
98
99 value[i] = LERP( fvalue, bvalue, fz );
100 }
101
102 finalvalue = LERP( value[0], value[1], ft );
103
104 return finalvalue;
105 }
106